1. Field of the Invention
The present invention relates to a liquid discharge head adapted for use in a liquid discharge recording apparatus, which discharges a liquid droplet by a discharge energy generated by a pressure generating element thereby forming an image on a recording medium, and a producing method therefor.
2. Related Background Art
In a recording apparatus of a liquid discharge method by discharging and depositing a liquid droplet on a recording medium thereby forming an image, microfine working and complex patterning are required for forming a structure with a larger number of nozzles, in order to meet the requirements for recording of high image quality and a high definition. Therefore producing methods for the liquid discharge head have been proposed, utilizing a micromachining technology, which can prepare fine and complex patterns in a simple manner on a monocrystalline silicon substrate for example by an anisotropic etching.
As an example, a producing method for an ink jet head, disclosed in Japanese Patent Application Laid-open No. H05-229128 is shown in FIG. 8. A flow path substrate 500 is constituted of a single crystal silicon substrate, and is subjected, on one surface thereof, to anisotropic etchings in two steps, thereby integrally forming an ink flow path including a nozzle 501, a pressure generation chamber 502, an ink supply opening 503, and a reservoir 504.
Also a producing method for an ink jet head, disclosed in Japanese Patent Application Laid-open No. H10-209113, is shown in FIGS. 9A to 9D. In forming a groove by an anisotropic etching on a single crystal Si (110) substrate 600, a groove forming mask pattern 601 is employed to reduce an area dependence of the etching rate. This step is shown in FIG. 9A, in which an etching is executed utilizing a mask pattern 601 having an aperture 602, thereby forming a narrow groove 603 as shown in FIG. 9B. Subsequently, a silicon portion 604 between these narrow grooves 603 is etched off as shown in FIG. 9C to form a wide groove 605 as shown in FIG. 9D.
The producing method disclosed in Japanese Patent Application Laid-open No. H05-229128, utilizing dependence of etching rate on the crystalline orientation, can form a reservoir with a high precision, but restrictions may result in the process since the usable crystalline orientation of single crystal silicon substrate is limited.
Also in case of forming a reservoir in a single crystal silicon substrate, when nozzles are formed with a high density by an anisotropic etching on an Si (100) substrate, the thickness of the substrate becomes inevitably smaller. It is therefore difficult to maintain a rigidity of the substrate, thus being unable to achieve an improved production yield and a durability and a stability of the head. Also in case of employing an Si (110) substrate, the process will become more difficult such as restriction on the freedom of shape, and requirement for multi-layered masks for regulating the depth of the reservoir.
The producing method disclosed in Japanese Patent Application Laid-open No. H10-209113 utilizes an anisotropic etching of a single crystal Si (110) substrate. Also in this case, restrictions may result in the process since the usable crystalline orientation of single crystal silicon substrate is limited.
In particular, a desired shape precision may not be met in case a groove to be formed has a complex non-rectangular shape, an etching depth varies within an etching aperture area, or a relatively large etching depth is required.